The pharmaceutical industry has developed a variety of techniques for delivering ophthalmic compositions, particularly those that include therapeutic agents, to the eye. Typical ophthalmic drug delivery techniques include topical application of ophthalmic compositions to the eye (e.g., by drops directly onto the eye) and intravitreal injections, which involve delivery of ophthalmic compositions to the vitreous of the eye with a needle (e.g., a syringe). Both of these techniques have drawbacks. One particular drawback common to both of these techniques is the frequency with which an individual must apply the ophthalmic compositions to best treat ophthalmic maladies such as glaucoma, age related macular degeneration (AMD) and others. Patients often forget or otherwise fail to administer drops to their eyes and patients can miss doctor appointments and fail to receive their needed injections.
In view of these drawbacks, the pharmaceutical industry has dedicated significant resources to the development of implantable drug delivery devices that provide sustained delivery of ophthalmic compositions and/or therapeutic agents to the eye. Such devices are typically designed to provide a continuous supply of therapeutic agent to the eye over an extended period of time.
Various ocular drug delivery implants have been described in an effort to improve and prolong drug delivery. For example, U.S. Pat. No. 3,949,750 discloses a punctal plug made of a tissue-tolerable, readily sterilizable material, such as Teflon, HEMA, hydrophilic polymer, methyl methacrylate, silicone, stainless steel or other inert metal material. It is stated that the punctal plug may be impregnated with ophthalmic medication or that the punctal plug may contain a reservoir of the ophthalmic drug.
U.S. Pat. No. 5,053,030 discloses an intracanalicular implant that can be used as a carrier or medium for distributing medications throughout the body. U.S. Pat. No. 5,469,867 discloses a method of blocking a channel, such as the lacrimal canaliculus by injecting a heated flowable polymer into the channel and allowing it to cool and solidify. The polymer may be combined with a biologically active substance that could leach out of the solid occluder once it has formed in the channel.
WO 99/37260 discloses a punctal plug made of a moisture absorbing material, which is not soluble in water, such as a modified HEMA. It is also disclosed that an inflammation inhibitor, such as heparin, may be added to the material from which the punctal plug is made.
U.S. Pat. No. 6,196,993 discloses a punctal plug containing glaucoma medication. The medication is contained in a reservoir within the plug. The reservoir is in fluid communication with a pore through which the medication is released onto the eye.
U.S. Pat. No. 4,592,752 discloses a corneal drug delivery device. The device is substantially the size and curvature of the cornea upon which it is placed and it includes an aperture substantially the size and shape of the pupil of the eye.
More recently, implantable devices have been developed for providing pulsatile or intermittent doses of therapeutic agent to the eye. Examples of such devices are disclosed in U.S. Pat. Nos. 5,725,493; 5,830,173; and 6,251,090 and U.S. Patent Publication No. 2008/0039792, all of which are specifically incorporated herein by reference for all purposes.
U.S. Patent Application No. 2008/0181930 discloses a drug delivery device having a body that includes a matrix of a therapeutic agent and another material such as silicon. The body is coated with a material such as parylene and one or more pores extend from the outer surface of the coating to the outer surface of the body to allow for release of therapeutic agent.
U.S. Provisional Patent Application No. 61/157,010, which is incorporated herein by reference for all purposes, discloses a peri-corneal drug delivery device. A preferred embodiment of the device includes an inner matrix core surrounded by an outer coating. The outer coating includes one or more openings extending to the core for allowing sustained drug release from the inner matrix core.
Each of these devices can provide for some degree of sustained delivery of an ophthalmic composition. However, these devices, as well as other conventional devices, typically suffer from one or more drawbacks. As one example, many conventional devices require that they be applied through an invasive surgical procedure. As another example, many conventional devices have difficulty delivering desired amounts of therapeutic agent for desired amounts of time. As another example, many conventional devices have difficulty delivering therapeutic agent in particular quantities at particular times as may be needed or desired. As yet another example, many devices have difficulty maintaining their desired location relative to the eye and can be lost or undesirably moved. As still another example, many conventional devices can cause discomfort. Thus, there is a need for an ophthalmic drug delivery device that can overcome one, two or more of these drawbacks.